This is a great video on modeling an abandoned farmhouse or shack for your wargames table.
The Earlswood site has instructions on using teddy bear fur to make patches of grass for your miniature wargames terrain.
Matakishi has some instructions with photos for making World War II era buildings out of sheets of cork.
Terrain Thralls has a photo tutorial on making terrain that looks like ice floes. They’re cleverly made from foam core, and is intended for Privateer Press’ Warmachine game, but I think it would be spectacular in a variety of fantasy settings. I can also envision a neat Frankenstein vs The Monster scenario.